Most standard wire mesh shopping carts have built in child seats near the handle-end of the cart. In many instances, mothers have two young children that must be accommodated while she shops. The present invention is directed to a portable child safety seat that is light in weight, is foldable so that it can easily be carried by the mother, and can be quickly and easily attached to a standard wire mesh shopping cart. The larger child can ride in the built in child seat while the smaller child can then be safely carried in the portable child safety seat of the present invention while the mother shops.